<?php


namespace think\admin;

use think\facade\Db;

/**
 * Class MysqlBackupService
 * @package app\admin\service
 * 数据库表备份
 */
class Backup
{

  /**
   * 文件指针
   * @var resource
   */
  private $fp;
  /**
   * 备份文件信息 part - 卷号，name - 文件名
   * @var array
   */
  private $file;
  /**
   * 当前打开文件大小
   * @var integer
   */
  private $size = 0;

  /**
   * 数据库配置
   * @var integer
   */
  private $dbconfig = array();
  /**
   * 备份配置
   * @var integer
   */
  private $config = array(
    'path' => './Data/',
    //数据库备份路径
    'part' => 20971520,
    //数据库备份卷大小
    'compress' => 0,
    //数据库备份文件是否启用压缩 0不压缩 1 压缩
    'level' => 9,
  );

  /**
   * 数据库备份构造方法
   *
   * @param array $file 备份或还原的文件信息
   * @param array $config 备份配置信息
   */
  public function __construct($config = [])
  {
    $this->config['path'] = app()->getRootPath() . 'backup/';
    $this->config = array_merge($this->config, $config);
    //初始化文件名
    $this->setFile();
    //初始化数据库连接参数
    $this->setDbConn();
    //检查文件是否可写
    if (!$this->checkPath($this->config['path'])) {
      throw new \Exception("The current directory is not writable");
    }
  }

  /**
   * 设置脚本运行超时时间
   * 0表示不限制，支持连贯操作
   */
  public function setTimeout($time = null)
  {
    if (!is_null($time)) {
      set_time_limit($time) || ini_set("max_execution_time", $time);
    }
    return $this;
  }

  /**
   * 设置数据库连接必备参数
   *
   * @param array $dbconfig 数据库连接配置信息
   * @return $this
   */
  public function setDbConn($dbconfig = [])
  {
    if (empty($dbconfig)) {
      $this->dbconfig = config('database.connections.' . config('database.default'));
      //$this->dbconfig = Config::get('database');
    } else {
      $this->dbconfig = $dbconfig;
    }
    return $this;
  }

  /**
   * 设置备份文件名
   *
   * @param null $file
   * @return $this
   */
  public function setFile($file = null)
  {
    if (is_null($file)) {
      $this->file = ['name' => date('Ymd-His'), 'part' => 1];
    } else {
      if (!array_key_exists("name", $file) && !array_key_exists("part", $file)) {
        $this->file = $file['1'];
      } else {
        $this->file = $file;
      }
    }
    return $this;
  }

  //数据类连接
  public static function connect()
  {
    return Db::connect();
  }

  /**
   * 数据库表列表
   *
   * @param null $table
   * @param int $type
   * @return array
   * @throws \think\db\exception\BindParamException
   * @throws \think\exception\PDOException
   */
  public function dataList(?string $table = null, int $type = 1)
  {
    $db = self::connect();
    if (is_null($table)) {
      $list = $db->query("SHOW TABLE STATUS");
    } else {
      if ($type) {
        $list = $db->query("SHOW FULL COLUMNS FROM {$table}");
      } else {
        $list = $db->query("show columns from {$table}");
      }
    }
    return array_map('array_change_key_case', $list);
    //$list;
  }

  /**
   * 数据库备份文件列表
   *
   * @return array
   */
  public function fileList()
  {
    if (!is_dir($this->config['path'])) {
      mkdir($this->config['path'], 0755, true);
    }
    $path = realpath($this->config['path']);
    $flag = \FilesystemIterator::KEY_AS_FILENAME;
    $glob = new \FilesystemIterator($path, $flag);
    $list = array();
    foreach ($glob as $name => $file) {
      if (preg_match('/^\\d{8,8}-\\d{6,6}-\\d+\\.sql(?:\\.gz)?$/', $name)) {
        $info['filename'] = $name;
        $name = sscanf($name, '%4s%2s%2s-%2s%2s%2s-%d');
        $date = "{$name[0]}-{$name[1]}-{$name[2]}";
        $time = "{$name[3]}:{$name[4]}:{$name[5]}";
        $part = $name[6];
        if (isset($list["{$date} {$time}"])) {
          $info = $list["{$date} {$time}"];
          $info['part'] = max($info['part'], $part);
          $info['size'] = $info['size'] + $file->getSize();
        } else {
          $info['part'] = $part;
          $info['size'] = $file->getSize();
        }
        $extension = strtoupper(pathinfo($file->getFilename(), PATHINFO_EXTENSION));
        $info['compress'] = $extension === 'SQL' ? '-' : $extension;
        $info['time'] = strtotime("{$date} {$time}");
        $list["{$date} {$time}"] = $info;
      }
    }
    return $list;
  }

  /**
   * @param string $type
   * @param int $time
   * @return array|false|string
   * @throws \Exception
   */
  public function getFile($type = '', $time = 0)
  {
    //
    if (!is_numeric($time)) {
      throw new \Exception("{$time} Illegal data type");
    }
    switch ($type) {
      case 'time':
        $name = date('Ymd-His', $time) . '-*.sql*';
        $path = realpath($this->config['path']) . DIRECTORY_SEPARATOR . $name;
        return glob($path);
        break;
      case 'timeverif':
        $name = date('Ymd-His', $time) . '-*.sql*';
        $path = realpath($this->config['path']) . DIRECTORY_SEPARATOR . $name;
        $files = glob($path);
        $list = array();
        foreach ($files as $name) {
          $basename = basename($name);
          $match = sscanf($basename, '%4s%2s%2s-%2s%2s%2s-%d');
          $gz = preg_match('/^\\d{8,8}-\\d{6,6}-\\d+\\.sql.gz$/', $basename);
          $list[$match[6]] = array($match[6], $name, $gz);
        }
        $last = end($list);
        if (count($list) === $last[0]) {
          return $list;
        } else {
          throw new \Exception("File {$files['0']} may be damaged, please check again");
        }
        break;
      case 'pathname':
        return "{$this->config['path']}{$this->file['name']}-{$this->file['part']}.sql";
        break;
      case 'filename':
        return "{$this->file['name']}-{$this->file['part']}.sql";
        break;
      case 'filepath':
        return $this->config['path'];
        break;
      default:
        $arr = array('pathname' => "{$this->config['path']}{$this->file['name']}-{$this->file['part']}.sql", 'filename' => "{$this->file['name']}-{$this->file['part']}.sql", 'filepath' => $this->config['path'], 'file' => $this->file);
        return $arr;
    }
  }

  /**
   * 删除备份文件
   * @param $time
   * @return mixed
   * @throws \Exception
   */
  public function delFile($time)
  {
    if ($time) {
      $file = $this->getFile('time', $time);
      array_map("unlink", $this->getFile('time', $time));
      if (count($this->getFile('time', $time))) {
        throw new \Exception("File {$time} deleted failed");
      } else {
        return $time;
      }
    } else {
      throw new \Exception("{$time} Time parameter is incorrect");
    }
  }

  /**
   * 下载备份
   *
   * @param $time
   * @param int $part
   * @throws \Exception
   */
  public function downloadFile($time, $part = 0)
  {
    $file = $this->getFile('time', $time);
    $fileName = $file[$part];
    if (file_exists($fileName)) {
      ob_end_clean();
      header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
      header('Content-Description: File Transfer');
      header('Content-Type: application/octet-stream');
      header('Content-Length: ' . filesize($fileName));
      header('Content-Disposition: attachment; filename=' . basename($fileName));
      readfile($fileName);
    } else {
      throw new \Exception("{$time} File is abnormal");
    }
  }

  public function import($start)
  {
    //还原数据
    $db = self::connect();
    if ($this->config['compress']) {
      $gz = gzopen($this->file[1], 'r');
      $size = 0;
    } else {
      $size = filesize($this->file[1]);
      $gz = fopen($this->file[1], 'r');
    }
    $sql = '';
    if ($start) {
      $this->config['compress'] ? gzseek($gz, $start) : fseek($gz, $start);
    }
    for ($i = 0; $i < 1000; $i++) {
      $sql .= $this->config['compress'] ? gzgets($gz) : fgets($gz);
      if (preg_match('/.*;$/', trim($sql))) {
        if (false !== $db->execute($sql)) {
          $start += strlen($sql);
        } else {
          return false;
        }
        $sql = '';
      } elseif ($this->config['compress'] ? gzeof($gz) : feof($gz)) {
        return 0;
      }
    }
    return array($start, $size);
  }

  /**
   * 写入初始数据
   *
   * @return boolean true - 写入成功，false - 写入失败
   */
  public function Backup_Init()
  {
    $sql = "-- -----------------------------\n";
    $sql .= "-- Think MySQL Data Transfer \n";
    $sql .= "-- \n";
    $sql .= "-- Host     : " . $this->dbconfig['hostname'] . "\n";
    $sql .= "-- Port     : " . $this->dbconfig['hostport'] . "\n";
    $sql .= "-- Database : " . $this->dbconfig['database'] . "\n";
    $sql .= "-- \n";
    $sql .= "-- Part : #{$this->file['part']}\n";
    $sql .= "-- Date : " . date("Y-m-d H:i:s") . "\n";
    $sql .= "-- -----------------------------\n\n";
    $sql .= "SET FOREIGN_KEY_CHECKS = 0;\n\n";
    return $this->write($sql);
  }

  /**
   * 备份表结构
   *
   * @param string $table
   * @param int $start
   * @return bool|int
   * @throws \think\db\exception\BindParamException
   * @throws \think\exception\PDOException
   */
  public function backup(string $table, int $start)
  {
    $db = self::connect();
    // 备份表结构
    if (0 == $start) {
      $result = $db->query("SHOW CREATE TABLE `{$table}`");
      $sql = "\n";
      $sql .= "-- -----------------------------\n";
      $sql .= "-- Table structure for `{$table}`\n";
      $sql .= "-- -----------------------------\n";
      $sql .= "DROP TABLE IF EXISTS `{$table}`;\n";
      $sql .= trim($result[0]['Create Table']) . ";\n\n";
      if (false === $this->write($sql)) {
        return false;
      }
    }
    //数据总数
    $result = $db->query("SELECT COUNT(*) AS count FROM `{$table}`");
    $count = $result['0']['count'];
    //备份表数据
    if ($count) {
      //写入数据注释
      if (0 == $start) {
        $sql = "-- -----------------------------\n";
        $sql .= "-- Records of `{$table}`\n";
        $sql .= "-- -----------------------------\n";
        $this->write($sql);
      }
      //备份数据记录
      $result = $db->query("SELECT * FROM `{$table}` LIMIT :MIN, 1000", ['MIN' => intval($start)]);
      foreach ($result as $row) {
        $row = array_map('addslashes', $row);
        $sql = "INSERT INTO `{$table}` VALUES ('" . str_replace(array("\r", "\n"), array('\\r', '\\n'), implode("', '", $row)) . "');\n";
        if (false === $this->write($sql)) {
          return false;
        }
      }
      //还有更多数据
      if ($count > $start + 1000) {
        //return array($start + 1000, $count);
        return $this->backup($table, $start + 1000);
      }
    }
    //备份下一表
    return 0;
  }

  /**
   * 优化表
   *
   * @param array|string $tables
   * @throws \think\db\exception\BindParamException
   * @throws \think\exception\PDOException
   */
  public function optimize($tables)
  {
    if ($tables) {
      $db = self::connect();
      if (is_array($tables)) {

        $tables = implode('`,`', $tables);

        $list = $db->query("OPTIMIZE TABLE `{$tables}`");
      } else {
        $list = $db->query("OPTIMIZE TABLE `{$tables}`");
      }

      if (!$list) {
        throw new \Exception("data sheet'{$tables}'Repair mistakes please try again!");
      } else {
        return $tables;
      }
    } else {
      throw new \Exception("Please specify the table to be repaired!");
    }
  }

  /**
   * 修复表
   *
   * @param string|null $tables
   * @return array
   * @throws \think\db\exception\BindParamException
   * @throws \think\exception\PDOException
   */
  public function repair(?string $tables = null)
  {
    if ($tables) {
      $db = self::connect();
      if (is_array($tables)) {
        $tables = implode('`,`', $tables);
        $list = $db->query("REPAIR TABLE `{$tables}`");
      } else {
        $list = $db->query("REPAIR TABLE `{$tables}`");
      }
      if ($list) {
        return $list;
      } else {
        throw new \Exception("data sheet'{$tables}'Repair mistakes please try again!");
      }
    } else {
      throw new \Exception("Please specify the table to be repaired!");
    }
  }

  /**
   * 写入SQL语句
   *
   * @param string $sql 要写入的SQL语句
   * @return boolean     true - 写入成功，false - 写入失败！
   */
  private function write(string $sql)
  {
    $size = strlen($sql);
    //由于压缩原因，无法计算出压缩后的长度，这里假设压缩率为50%，
    //一般情况压缩率都会高于50%；
    $size = $this->config['compress'] ? $size / 2 : $size;
    $this->open($size);
    return $this->config['compress'] ? @gzwrite($this->fp, $sql) : @fwrite($this->fp, $sql);
  }

  /**
   * 打开一个卷，用于写入数据
   *
   * @param integer $size 写入数据的大小
   */
  private function open(int $size)
  {
    if ($this->fp) {
      $this->size += $size;
      if ($this->size > $this->config['part']) {
        $this->config['compress'] ? @gzclose($this->fp) : @fclose($this->fp);
        $this->fp = null;
        $this->file['part']++;
        Session::set('backup_file', $this->file);
        $this->Backup_Init();
      }
    } else {
      $backuppath = $this->config['path'];
      $filename = "{$backuppath}{$this->file['name']}-{$this->file['part']}.sql";
      if ($this->config['compress']) {
        $filename = "{$filename}.gz";
        $this->fp = @gzopen($filename, "a{$this->config['level']}");
      } else {
        $this->fp = @fopen($filename, 'a');
      }
      $this->size = filesize($filename) + $size;
    }
  }

  /**
   * 检查目录是否可写
   *
   * @param string $path
   * @return bool
   */
  protected function checkPath(string $path)
  {
    if (is_dir($path)) {
      return true;
    }
    if (mkdir($path, 0755, true)) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * 析构方法，用于关闭文件资源
   */
  public function __destruct()
  {
    $this->config['compress'] ? @gzclose($this->fp) : @fclose($this->fp);
  }
}
